I use an air chamber. (£400)
It is brilliant, 2 filtered fans run continuously (electric costs approx £30 per year) pushing and circulating 50,000 litres of air every hour.
The results are fantastic. No condensation or moisture, no dust and an ambient temp that actually dries the vehicle as well.
It is big enough for you to clean, valet or work on the car whilst it is in the air chamber.
A good value for money item
http://www.airflow-uk.com/air-chamber.htmdmat
